The present invention generally relates to die packaging, and more particularly to methods for forming a die package, specifically adapted for use in implantable medical devices (IMDs).
Die packaging has continued to receive a significant amount of attention from designers and manufacturers of electronic products. This attention is based upon the market demand for products with greater efficiency, higher performance, and smaller dimensions. The market demand for smaller dimensions is driven to at least some extent by portable electronic product applications, such as Implantable Medical Devices (IMDs).
As the dimensions of an IMD package becomes smaller and smaller, and as more and more components are added to such a device, the area is reduced within the IMD package that is available for the additional components. Furthermore, as the dimensions of the components are also shrinking, it is desirable to improve the use of all three dimensions within the IMD package. While die packages have been designed and manufactured that improve the utilization of all three dimensions within electronic packages, including portable electronic packages such as IMD packages, improvements are sought for the methods of forming the die package. For example, designers and manufactures seek improvements in the efficiency and cost effectiveness of these methods.
In view of the foregoing, it should be appreciated that it would be desirable to provide a method for forming a die package. In addition, it would be desirable to improve the methods for forming a die package, such as improving the efficiency and cost effectiveness of such methods. Furthermore, additional desirable features will become apparent to one of ordinary skill in the art from the foregoing background of the invention and following summary, brief description of the drawings, detailed description of the drawings, and appended claims.
In accordance with the teachings of the present invention, a method is provided for forming a die package. The method comprises stiffening a flexible substrate to provide a first flexibility of the flexible substrate, forming a mounting element on a first side of the flexible substrate, and mounting a first die on the first side of the flexible substrate to couple the first die to the mounting element. In addition, the method comprises mounting a second die on a second side of the flexible substrate to couple the second die to the mounting element and mounting a third die on the second side of the flexible substrate to couple the third die to the mounting element. Furthermore, the method comprises adjusting the stiffening to provide a second flexibility of the flexible substrate that is greater than the first flexibility, and stacking the second die and the third die to provide an overlap of a portion of the second die and a portion of the third die.